Definition
The rate at which temperature changes across a distance, expressed as the change in degrees per unit of distance (vertical or horizontal). In aviation, vertical temperature gradient describes how air temperature changes with altitude, typically given in degrees Celsius per 1,000 feet.
Plain English
How fast the temperature changes as you move from one place to another, usually as you climb or descend through the atmosphere.
Context Anchor
Seen in aviation weather discussions, especially when describing how temperature changes with altitude, across a front, or over different ground surfaces.
Derivation
From Latin gradus, meaning 'step' or 'degree.' A gradient is literally a stepwise change. Combined with 'temperature,' it means the stepwise change in temperature across a distance.
Why Pilots Care
Affects air density, engine output, lift, and the risk of icing or turbulence.
Grounding Statement
On a standard day, climbing from the surface to 10,000 feet, the temperature drops about 2°C per 1,000 feet -- that drop rate is the temperature gradient.
Intuition Check
Do not read temperature gradient as just the temperature. It means how fast temperature is changing over distance or altitude.
Example Sentence 1
The steep temperature gradient that afternoon produced strong convective activity along our route.
Example Sentence 2
A shallow temperature gradient near the surface kept the air stable during the morning takeoff.